1. Technical Field
This invention relates generally to metal casting and more particularly to vacuum-assisted gravity pour casting apparatus.
2. Related Prior Art
Gravity casting is conventionally used to manufacture metal cast articles having a variety of geometrical configurations. Difficulties have been encountered, however, when casting articles of intricate shape and/or thin section using conventional gravity pour casting, as such articles have a tendency to not fully develop during casting.
Before this invention, various vacuum-assisted gravity pour casting apparatus have been proposed which could be utilized for producing articles of intricate shape and/or thin section. Exemplary of such apparatus are those disclosed in U.S. Pat. No. 4,055,216, granted Oct. 25, 1977, in the name of Ulyanov et al.; and U.S. Pat. No. 4,541,475, granted Sep. 17, 1985, in the name of Goddard et al. Each discloses a vacuum chamber enclosing both a melting vessel and a casting mold. A vacuum chamber of such size, however, is expensive to manufacture and operate and hence limited in application. Equipment is further required for cycling the pouring vessel into and out of the chamber and melting metal within the vessel before pouring.